کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
943049 925182 2007 18 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Electrophysiological Measures of Maintaining Representations in Visual Working Memory
موضوعات مرتبط
علوم زیستی و بیوفناوری علم عصب شناسی علوم اعصاب رفتاری
پیش نمایش صفحه اول مقاله
Electrophysiological Measures of Maintaining Representations in Visual Working Memory
چکیده انگلیسی

Visual working memory (WM) is a limited capacity system which maintains information about objects in the immediate visual environment. Recent neurophysiological and neuroimaging studies have identified sustained memory-item specific activity during the retention period of WM tasks, and this activity may be a physiological substrate of maintaining representations in WM. In the present study, we present an electrophysiological measure of delay activity using event- related potentials (ERPs). Subjects were asked to remember the items in a single hemifield presented within a bilateral display. Approximately 200 msec following the onset of the memory array, we observed a large negative wave at electrode sites that were contralateral with respect to the position of the memory items. This activity persisted throughout the retention period and appears to be an analog to delay activity observed in monkey single-unit and functional magnetic resonance imaging (fMRI) WM studies. The contralateral delay activity is modulated by the number of items in the memory array but reaches asymptote for arrays of 3 to 4 items. This activity is similar across different classes of simple objects and the amplitude is smaller on incorrect response trials relative to correct trials, suggesting that this activity is necessary for correct performance on a given trial. Together, these results appear to indicate an electrophysiological index of the maintained representations in visual WM.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Cortex - Volume 43, Issue 1, 2007, Pages 77–94
نویسندگان
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